This proposal will establish a unique training program in a developing area of transdisciplinary research, co-occurring substance use and other mental disorders (COD). The need for this scientific focus is vital given that COD is more the norm than the exception among those with addictive disorders. The philosophy of this program asserts that to effectively impact the problems of addiction and mental illness, one must be fully aware of their co-existence, etiologies, phenomenology, and clinical manifestations. Moreover, knowledge of clinical approaches and the healthcare systems that serve those with addiction and mental illness is necessary to inform the questions to be asked in laboratory and clinical research studies. Embracing COD as a primary perspective is not a widely accepted approach for the training of scientists. Of NIDA's approximate sixty T32 programs, none include the words co-morbidity, dual diagnosis, or other indicators of a focus on COD. Establishing programs that prioritize training in this area will lead to the development of advanced methods for finding innovative strategies for serving those with COD. We propose to develop such a program by utilizing the unique resources and opportunities available at Dartmouth. Six interconnected groups will provide research opportunities in social, behavioral, and neurobiological mechanisms, treatment development (psychosocial and pharmacological), technology-assisted treatment and dissemination, and health services practices and implementation. Faculty include preeminent leaders in COD research, MD and PhD investigators with strong histories of training scientists, and a team of support faculty committed to establishing a structured training program in COD. Research teams include neuroscientists, behavioral health technologists, clinical trials and contingency management experts, anthropologists, statisticians, economists, and family therapists. Currently the faculty has 27 NIH-funded projects (NIDA [12], NIAAA [4], NIMH [8], NCI [2]; NICHD [1]), and multiple foundation, Department of Education, and VA supported studies. Predoctoral and postdoctoral students mentored by core faculty in the past 10 years have co-authored over 150 publications related to their training activities and were first author on approximately 50% of those. This program will train 5-7 predoctoral and 9-11 postdoctoral students in the initial funding period. The stellar reputation of the faculty and participating research programs, in concert with rigorous criteria for trainee selection and a strong commitment to attracting diverse trainees, will ensure the development of scientists with greater knowledge about the scope of issues that science must address to effectively impact addiction and mental illness. This cohort will be more equipped with broad areas of expertise and a commitment to multidisciplinary approaches to their questions of interest.